Peptide antagonists of substance P and of LHRH are described in U.S. Pat. Nos. 4,481,139 and 4,481,190, respectively.
Neurokinin B, also known as .beta.-neurokinin and neuromedin K, recently has been isolated from porcine spinal cord; Kimura, s., et al, Proc. Jap. Acad. Ser. B, 59: 101 (1983) and Kangawa, K., et al., Biochem. Biophys. Res. Comm., 114: 533 (1983). This decapeptide has the following formula: EQU Asp.sup.1 -Met.sup.2 -His.sup.3 -Asp.sup.4 -Phe.sup.5 -Phe.sup.6 -Val.sup.7 -Gly.sup.8 -Leu.sup.9 -Met.sup.10 -NH.sub.2.
This decapeptide has the same C-terminal sequence shared by all tachykinins, but its N-terminal region is strikingly different especially when compared to that of substance P. Neurokinin B has two aspartic acid residues (a negatively charged peptide) while substance P has an arginine and lysine residue (positive charges) in this region. Antagonists to substance P have been developed as reviewed by Regoli, D., et al., Pharmacology 28: 301 (1984). As yet no antagonists of Neurokinin B have been described. The substitution of D-Pro for Pro.sup.2 and Phe.sup.7 and Gly.sup.9 by D-Trp results in an antagonist of substance P which has analgesic properties; Akerman, B., et al., Acta Physio. Scand. 114: 631 (1982). Neurokinin B has different biological properties from substance P which may be representative of the large difference in the N-terminal region of these two peptides; Vaught, J. L., et al., Europ. J. Pharmacol. 103: 355 (1984); Munekata, E., et al., Chem. Lett., 1013 (1984).